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  • 1
    Electronic Resource
    Electronic Resource
    Surface diffusion in liquid-filled pores (1974)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 20 (1974), S. 1110-1117 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Surface diffusivities of benzaldehyde in liquid-filled pores of Amberlite particles (polystyrene) were measured at 25°C using water as a solvent. For particles of different surface areas but chemically similar pore surfaces, the intrinsic surface diffusivity Ds' was about the same, but the relative importance of surface to pore-volume diffusion increased with surface area. For a single type of particle, the adsorption capacity was decreased about twenty-fold by adding up to 19 mole % methanol to the solvent. This was accompanied by an increase in Ds' from 1.2 × 10-8 to 1.2 × 10-7 cm2/s. These results were interpreted in terms of a two-step theory for surface migration: (1) formation of a vacant site on the adsorbent surface followed by (2) movement of the adsorbate molecule into the site by breaking the surface-adsorbate bond. The theory predicts that surface transport will be large when the surface area is high and that the Ds' will be large when the heat of adsorption is low, and when the bond between solvent molecules and the surface is weak.In our studies the surface contribution to intraparticle transport was as much as 20 times the contribution due to pore-volume diffusion. This ratio increases as the concentration of adsorbate in the liquid decreases.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690200608
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  • 2
    Electronic Resource
    Electronic Resource
    Intraparticle mass transport in liquid-filled pores (1974)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 20 (1974), S. 728-734 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Adsorption rate data were measured at 25° to 75°C for benzaldehyde on polymeric, porous Amberlite particles. When the benzaldehyde is dissolved in methanol, the adsorption capacity is very low. Data for methanol solutions gave reasonable values for intraparticle diffusivities based solely on transport in the pore volume. For adsorption from aqueous solution (where the adsorption capacity was high), the contribution of surface diffusion was important.From the two sets of data it was possible to evaluate average effective surface diffusivities by using a model based upon both pore-volume and surface transport. These values were about 10-8 cm2/s and were sufficiently sensitive to temperature to give activation energies of 7 to 9 k cal/mole.For the more hydrophobic Amberlite, XAD-4, surface transport was many times as large as pore-volume diffusion.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690200414
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  • 3
    Electronic Resource
    Electronic Resource
    Sulfur dioxide oxidation in slurries of activated carbon. Part II. Mass transfer studies (1975)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 21 (1975), S. 670-676 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bubble-to-liquid, liquid-to-particle, and intraparticle mass transport effects were all found to be significant for some conditions in a three-phase slurry reactor operated for the oxidation of SO2 at 25°C and 1 atm. In particular, intraparticle diffusion was important for particles as small as 99 microns (effectiveness factor = 0.45).Effective diffusivities determined from reaction, desorption, and adsorption data for O2, H2SO4, and SO2 indicated that surface diffusion was appreciable for SO2 but not for oxygen. These results are consistent with the kinetic results in Part I which suggested that the rate-controlling step was a chemisorption process for oxygen on the pore surface of the carbon particles.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690210405
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  • 4
    Electronic Resource
    Electronic Resource
    Sulfur dioxide oxidation in slurries of activated carbon. Part I. Kinetics (1975)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 21 (1975), S. 664-670 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dynamic adsorption and reaction studies were made for the catalytic oxidation of sulfur dioxide in aqueous slurries of activated carbon at room temperature and atmospheric pressure. For the small particles (dp = 0.03 mm) of carbon used, mass transfer resistances were of minor importance so that the data could be analyzed in terms of the kinetics of the chemical reaction. Quantitative evaluation of mass transfer effects, including intraparticle diffusion, is presented in Part II.The rate was first order in oxygen concentration in the liquid and zero order with respect to SO2. The rate decreased with increasing H2SO4 concentration in the liquid. This was explained by the decrease in solubility of oxygen in the solution rather than by a change in reaction rate constant. The adsorption and rate data together suggest that the controlling step in the mechanism is the adsorption of oxygen on active sites of the carbon surface. The low concentration of oxygen in water (due to its low solubility) reduces its rate of adsorption.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690210404
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  • 5
    Electronic Resource
    Electronic Resource
    Kinetics on the dissolution of CO2 into water from the surface of CO2 hydrate at high pressure (1995)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 27 (1995), S. 569-575 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Kinetic study on the dissolution of CO2 from the surface of a liquid CO2 droplet in water was conducted, and a mechanism of the decay of CO2 hydrate was proposed. The model was applied to the experimental data which showed that the radius of liquid CO2 droplets in water reduced linearly with time. It was proved that the dissolution rate of CO2 into water is dominated by the decay of CO2 hydrate on the surface of the droplet. The rate constant of the decay of CO2 hydrate was estimated to be 1.25 × 10-6 m s-1. From a viewpoint of liquid CO2 disposal in the deep ocean, it is predicted that the thin membrane of CO2 hydrate at the interface between seawater and liquid CO2 will control the dissolution of CO2 into seawater. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550270607
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  • 6
    Electronic Resource
    Electronic Resource
    Kinetics and mechanism of the formation of CO2 hydrate (1993)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 25 (1993), S. 777-782 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article proposes a mechanism of CO2 hydrate formation taking into account both diffusion and reaction, and gives an analysis of its kinetics. The most important assumptions on the model are that water dissolves into liquid CO2 and reacts to form CO2 hydrate, and that the hydrate blocks the dissolution and diffusion of water. Computational simulations were conducted, and the model proposed explains well the many observations on the CO2 hydrate formation in previous articles. It is concluded that liquid CO2 disposed in a deep ocean will form a very thin film of CO2 hydrate, and this will greatly control the CO2 diffusion in the ocean. © 1993 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550250908
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  • 7
    Electronic Resource
    Electronic Resource
    Dissolution and dispersion of CO2 from a liquid CO2 pool in the deep ocean (1995)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 27 (1995), S. 1089-1095 
    Details
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Liquid CO2 sequestration in a bathymetric depression at depths greater than 3700 m in the ocean has been proposed as a mitigation strategy for the reduction of atmospheric CO2 emissions. Kinetic studies on the dissolution of CO2 from the liquid CO2 pool, the diffusion in the ocean, and advection of CO2 by the bottom ocean current are carried out. A thin membrane of CO2 hydrate on the liquid CO2 pool controls the CO2 dissolution into the overlaying seawater, the thickness of a static layer between the surface of liquid CO2 and the upper bottom ocean current reduces the CO2 diffusion, and the bottom ocean current dilutes the CO2 concentration. These effects are explicity formulated in an equation, and it is predicted that ocean CO2 sequestration at a depth larger than 3700 m will greatly reduce the pH change caused by CO2 dispersion in the ocean. © 1995 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/kin.550271106
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